Aluminum disk suitable for use in manufacturing circular articles



y 2, 1939- K. TAKEDA 2,156,439

ALUMINUM DISK SUITABLE FOR USE IN MANUFACTURING CIRCULAR ARTICLES Filed March 5, 1937 Mum-N70 (swJ/eo Tg (gpgl Patented May 2, 1939 UNITED STATES ALUMINUM DISK MANUFACTURE G SUITABLE Fon use m cmo ULAB ARTICLES Kenjiro Takeda, Tosaboridori, Nishiku, Osaka, Japan Application March 5, 1937, Serial No. 129,285

' In Japan October 10, 1936 1 Claim.

This invention relates to aluminum disks suitable for use in manufacturing circular articles, and has for its object to increase the efficiency, of production and also to strengthen the durability of the circular articles made of the said disks.

According to thmethod. of manufacture of circular articles such as washing-basins or pots with aluminum disks by employing apress for shaping as hithertofore in practice, the disks being piled up are annealed in an annealing furnace for ten hours or more, and then each of the said disks is shaped to the desired size of the circular articles by means of the press. In such treatment, the side-wall of the article becomes somewhat hardened as a result of compression effected thereon and stress increased accordingly. However, the bottom part remains in a state of being annealed, i. 'e the section of the said part has a soft granular structure as shown under a microscope, and also the said part is extended thinner due to its greater extensibility as 'compared with the other parts. Consequently, on account of the above fact concave spots are apt to take place soon in using the articles in the bottom part or at the surrounding corners thereof; such defects are usually seen in using articles manufactured by the method heretofore taken. while, according to the present invention, it is possible to avoid such defects in an effective manher as fully described hereinafter with reference to the accompanying drawing.

In the accomp nying drawing, Figure 1 shows a perspective view of an aluminum disk according to this invention, Figure 2 shows a longitudinal sectional view thereof, Figure 3 shows an enlarged view of a main part of Figure -2 and Figure 4- shows a side elevation of a revolving press for shaping to which the disk of thisinvention'is applied and worked; the disk is shown in section.

According to this invention, an aluminum disk treated under a suitable heat treatment comprises an inner circular zone 3 of hard structure slightly concaved towards the centre, and an outer annular zone 2 of soft structure integrally formed with the said inner circular zone at the periphery of the latter. An intermediatezone l formed between the said both zones 2 and I imder the heat treatment of the disk is almost so hard asthe inner circular zone 3 because of its being half annealed owing to its position situated intermediately between the soft annealed zone 2 and the hard non-annealed zone I. The aluminum disk which is pow turnedinto the form of a lotus leaf as a result of the above treatment as .shown in Figures 1 and 2, retains its-original hardness in the bottom part, i. e., the section of the said part maintains the fibre-structure as shown under a microscope. Consequently, the original hardness and strength of the-material are completely preserved in the bottom part, and moreover, the

natural lustre pertaining to the material is not affected in the said part during the treatment so that much troubles in the finish-polishing can be saved.

In the manufacture of circular articles by using the aluminum disk I according to this invention, the said disk is applied either to a revolving press for shaping as shown in Figure 4, or is applied to a press provided with male and female dies.

In case of working the disk by the revolving press for shaping, the said disk I is pressed slightly against the surface of a mould 5 by a pusher 6 and revolved until it takes its center slip between the said mould and disk cannot be avoided so that the mould damages the surface of the disk, that is to say, the surface of the disk gets scratches in the form of volute or concentric circle caused by the sands or the like still remaining adhered on the disk I or the mould 5,

and those traces are kept unefl'aced even after the completion of the shaping. Thus, the satisfactory good appearance of the products cannot be obtained.

0n the contrary, asin the disk I of this invention, when the disk I is made to take a slight concavity at the inner circular zone I, the disk .can be held tight on the surface of the mould by the intermediate annular zone. 4 of the said disk around the concave inner circular zone I, and effects revolving in company with the mould due to the high degree of resisting friction between the both so that no trace of scratches is found on the surface of the article when completed.

Also, in. case ofusing the pressprovided with male and female dies, much practical advantages can be realized, because it is very facile to fix the disk I in its proper position when the said disk is attached to the dies.

I claim,

An aluminum disk suitable for use in manufacturing a circular'article wherein the disk is so constructed as-to comprise an inner circular zone of hard structure and an outer annular zone of soft structure integrally formed with the circular zone at the periphery of the latter, the inner circular zone being slightly concaved towards the,

centre when the outer annular zone is annealed before the disk is placed upon a shaping mold or I dies for shaping it to the-desired form.

'KENJIRO TAKEDA. 

